The present invention relates to a plasma reactor for flexible strand material.
Flexible strand materials, e.g., wires, irregular fiber bundles such as, e.g., sliver combings of natural wool, or regular fiber knits and fiber braidings, e.g., technical textiles, are used as raw materials and intermediate products in many branches of industry. To prepare such strand materials for the subsequent processing step, chemical treatment methods are frequently used by means of which the surface of the strand material is modified. Since chemical treatment methods often involve considerable environmental impairments, attempts have been made to subject the mentioned strand materials to a plasma treatment (PVD, CVD, plasma etching) which results in a lower environmental impact as compared to chemical processing methods.
To be able to subject flexible strand materials to a continuous plasma treatment, plasma reactors have been developed as pilot plants, comprising a reactor chamber into which the strand material is guided via an entrance passage and out of which it is guided via an exit passage. Electrodes are arranged in the interior of the reactor chamber, generating a plasma through which the strand material is moved.
To be able to achieve a good result with the plasma treatment, it is required that the strand material to be processed is exposed to the influence of the plasma for several minutes. Such a long processing time can be achieved when the strand material is guided on a meander-shaped path in the interior of the plasma reactor. With known plasma reactors, the guidance is effected by guiding elements guiding the strand material along a processing path. In spite of such a guidance, the known plasma reactors are very elongated apparatus in which a plurality of serially connected electrodes is provided each of which generates small, local plasmas. The plurality of electrodes, however, are difficult to control and there is the danger of a local thermal destruction of the strand material to be processed. Moreover, the guiding elements guiding the strand material have a negative effect upon the development of the plasma and the control thereof.
Apart from the disadvantage of a great structural length and a strand guidance susceptible to errors, the known plasma reactors thus also have the disadvantage of an insufficient controllability and an insufficient processing quality.